Scrollable Content Script II Embedded Video issue

1) Script Title: Scrollable Content Script II

2) Script URL (on DD): http://www.dynamicdrive.com/dynamicindex11/scrollc2.htm

3) Describe problem: I embedded a YouTube video in a scrollable area on the page. The video scrolls properly in Internet Explorer 7 and Safari 3.1, that is the video disappears at the top of the scrollable area. In Firefox 3.0.1, the video doesn't disappear at the top of the scrollable area but remains visible until it disappears at the top of the browser's viewable area. When I scroll back up to the top of the page, the video reappears at the top of the viewable area and scrolls back down to the appropriate location on the page. Is this a bug?

I have the exact same problem with Firefox. It is not only youtube videos but any type of embeded media. The only thing I can add from my investigations regarding this problem is that it is not that the video remains visible until it disappears at the top of the browser window as it appears. Actually the embedded media does become hidden but only when the the ENTIRE object has reached the edge of the visible content area. For example, if you are scrolling down a page (and the content is moving upwards) the media will hide as soon as its bottom edge hits the top of the content area. Not sure how to solve this issue.